Chemical light devices are useful for providing a source of non-electric light and have become exceedingly popular especially for emergency and outdoor use. Typical chemical light devices contain two liquids that produce light upon mixing. Typically, one of these liquids was referred to as an oxalate solution. It typically contained a carrier solvent, an oxalate ester, and a fluorescer. The second liquid was referred to as an activator solution. It typically contained a carrier solvent, hydrogen peroxide, and a catalyst.
The oxalate ester is the component of the system which is most deleteriously affected by moisture, although other components such as yellow and blue fluorescers and salicylate catalysts may also be affected. The instant invention provides oxalate esters, methods of synthesis of said esters, and methods for the prevention of the deterioration of the oxalate esters.
A typical commercially available chemiluminescent device of the dual container variety contains a diluent solution of oxalate ester and fluorescer in the outer container and a diluent solution of hydrogen peroxide and catalyst in the inner container. Typical devices are disclosed in one or more of the following U.S. Pat. Nos. 3,511,612; 3,539,794; 3,576,987; 3,584,211; 3,654,525; 3,749,620; 3,752,406; 3,800,132; 3,808,414; 3,940,604; 3,974,368; 4,064,428; each of which is hereby incorporated herein by reference.
The chemiluminescent light is obtained by the reaction of the hydrogen peroxide of the activator solution with the chemiluminescent composition which comprises the oxalate ester, fluorescer, and catalyst. Typical oxalate esters have heretofore included compounds such as bis(2-nitrophenyl) oxalate, bis(2,4-dinitrophenyl) oxalate, bis(2,6-dichloro-4-nitrophenyl) oxalate, bis(2,4,6-trichlorophenyl) oxalate, bis(3-trifluoromethyl-4-nitrophenyl) oxalate, bis(2-methyl-4,6-dinitrophenyl) oxalate, bis(1,2-dimethyl-4,6-dinitrophenyl) oxalate, bis(2,4-dichlorophenyl) oxalate, bis(2,5-dinitrophenyl) oxalate, bis(2-formyl-4-nitrophenyl) oxalate, bis(pentachlorophenyloxalate, bis(1,2-dihydro-2-oxo-1-pyridyl)glyoxal, bis-N-phthalmidyl oxalate. The preferred oxalate, is bis{3,4,6-trichloro-2-[(pentoxy)carbonyl]phenyl}oxalate.
The extreme sensitivity of these oxalates to water hydrolysis has created the need to package them carefully and store under refrigerated conditions. Water can and will migrate, at varying rates, through most non-metal and non-glass materials of construction. If the prior art oxalate esters were not packaged within a polymer lined metal (foil) pouch that is then stored in an inert (dry) gas containing metal drum that is stored under refrigerated conditions, the oxalate ester would hydrolyze and would fail to retain commercially viable shelf life.
The present invention discloses a novel family of branched chain oxalate esters which are useful in chemical lighting systems while being substantially non-hydrolyzing, thus eliminating the need for such careful and expensive handling and packaging requirements. This satisfies a long felt need in the art.